Dinosaurs apparently died out due to an asteroid and not a comet

The scientific debate about whether a comet or an asteroid hit the earth 66 million years ago and led to the extinction of the dinosaurs has been given a new perspective. Based on ruthenium isotope data, a group of researchers has concluded that an asteroid and not a comet was responsible for the mass extinction. According to the international team, they have found evidence suggesting that a carbonaceous asteroid struck near Chicxulub in present-day Mexico. This conclusion is based on an innovative method in which ruthenium isotopes are used to determine impact craters, as reported in an article in the journal Science.

Earlier chemical analyses, based on platinum metal contents and chromium isotopes, already pointed to a so-called ‘carbonaceous chondrite’ – a very original, carbon-rich type of stony meteorite, the scientists explain. In recent years, alternative theories have been put forward, including the possibility of a comet impact. The research team has now analysed rock samples from the crater created by the impact. ‘The new ruthenium isotope data clearly prove that the Chicxulub impact body was a carbonaceous asteroid that originally formed far outside Jupiter’s orbit,’ explains Christian Köberl from the University of Vienna. This does not support the hypothesis of a comet impact.

This hypothesis was put forward by two US scientists around three years ago. Using statistical analyses and simulations, they came to the conclusion that a comet that was hurled from Jupiter towards the sun and broke up there could have hit the earth on its way back. This origin would explain the unusual composition of the impactor, including the carbonaceous chondrites.

In the current study, the research team is focussing on the geochemical analysis of the rocks in impact craters. Ruthenium is only found in very small quantities in terrestrial rocks, while higher concentrations indicate a meteoritic origin. The results of the new analysis technique are promising and could make a decisive contribution to identifying impacts and the composition of impactors on Earth in the future, according to the researchers.

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Sladjan Lazic

Sladjan ist Triops-Züchter und Gründer von Triops Galaxy. Im Jahr 2020 hat er seine Leidenschaft für Urzeitkrebse entdeckt und züchtet seitdem diese faszinierenden Urzeitwesen in heimischer Zucht.

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